The present invention relates to a tool head structure of power screwdriver, which includes less parts and can be easily manufactured and assembled. The tool head structure can be durably used with better driving effect and can be easily carried. The tool head structure is applicable to power tools such as power screwdriver for tightening and untightening car tire screws.
Power tools are widely used in various fields to facilitate operation and save time and labor. For example, a power socket wrench is used to untighten and tighten the screws (nuts) of a car tire to facilitate detacment and installation of the car tire. In the power socket wrench, the socket is driven by a motor via a driving mechanism so as to easily tighten and untighten the screws or nuts.
FIG. 10 shows a clutch and driving mechanism of a conventional power screwdriver, including a base 10, a driving member 20, a driven member 30, a pivot shaft 40, a clutch 50 and two pin members 60. The base 10 is formed with a central hole 100. The wall of the base 10 is formed with a notch 101 communicating with the central hole 100. The clutch 50 is disposed with a front panel 51 for connecting the clutch 50 with one end of the base 10. An output shaft of a motor is coupled with the clutch for driving the base to rotate. The driving member 20 is formed as an arch block and pivotally connected with upper portion of the notch 101 via the pivot shaft 40. The driving member 20 is freely swingable about the pivot shaft 40 in the notch 101. The front end of the driven member 30 is formed with tooth blocks 301. The rear end of the driven member 30 is disposed with a square connector for connecting with the socket. The tooth blocks 301 are positioned into the central hole 100 of the base 10. Each pin member 60 is formed with an annular groove 601. The front panel 51 of the clutch 50 is formed with two slots 501. The pin members 60 are fitted into the slots 501 at the annular grooves 601 and extended into the through holes 102 of the base. In normal state, the pin members 60 are locked at lower end of the driving member 20. After the clutch 30 is rotated at high speed, the pin members 60 are backward retracted into the through holes 102 of the base 10. During swinging, two ends of the driving member 20 collide the driven member 30 in the central hole so as to rotate the driven member 30 and indirectly drive the socket.
According to the above arrangement, when the driving member 20 collides the tooth blocks 301 of the driven member 30, the driving member 20 will suffer a reaction force which forms a shear force exerted onto the pivot shaft 40. This may lead to damage of the pivot shaft.